diff --git a/sw/ground_segment/python/settings_app/settingsapp.py b/sw/ground_segment/python/settings_app/settingsapp.py
index 9f7eae3080c..16c36006f45 100755
--- a/sw/ground_segment/python/settings_app/settingsapp.py
+++ b/sw/ground_segment/python/settings_app/settingsapp.py
@@ -7,7 +7,9 @@
 import getopt
 import sys
 
-sys.path.append(os.getenv("PAPARAZZI_HOME") + "/sw/lib/python")
+PPRZ_SRC = os.getenv("PAPARAZZI_SRC", os.path.normpath(os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                                                      '../../../..')))
+sys.path.append(PPRZ_SRC + "/sw/lib/python")
 import settings_xml_parse
 
 def Usage(scmd):
diff --git a/sw/ground_segment/python/settings_app/settingsframe.py b/sw/ground_segment/python/settings_app/settingsframe.py
index ce0d7e14fe8..65f775703b2 100644
--- a/sw/ground_segment/python/settings_app/settingsframe.py
+++ b/sw/ground_segment/python/settings_app/settingsframe.py
@@ -6,7 +6,9 @@
 import sys
 import os
 
-sys.path.append(os.getenv("PAPARAZZI_HOME") + "/sw/lib/python")
+PPRZ_SRC = os.getenv("PAPARAZZI_SRC", os.path.normpath(os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                                                      '../../../..')))
+sys.path.append(PPRZ_SRC + "/sw/lib/python")
 
 from settings_tool import IvySettingsInterface
 
diff --git a/sw/lib/python/settings_tool.py b/sw/lib/python/settings_tool.py
index 6e8b313911d..6be73172b92 100755
--- a/sw/lib/python/settings_tool.py
+++ b/sw/lib/python/settings_tool.py
@@ -7,7 +7,9 @@
 import logging
 import sys
 
-sys.path.append(os.getenv("PAPARAZZI_HOME") + "/sw/lib/python")
+PPRZ_SRC = os.getenv("PAPARAZZI_SRC", os.path.normpath(os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                                                      '../../..')))
+sys.path.append(PPRZ_SRC + "/sw/lib/python")
 from settings_xml_parse import PaparazziACSettings
 
 _SHOW_IVY_MSGS_ = False
diff --git a/sw/lib/python/settings_xml_parse.py b/sw/lib/python/settings_xml_parse.py
index 5f2602221c5..151ef3f7b6e 100755
--- a/sw/lib/python/settings_xml_parse.py
+++ b/sw/lib/python/settings_xml_parse.py
@@ -6,6 +6,10 @@
 import sys
 from lxml import etree
 
+# if PAPARAZZI_HOME not set, then assume the tree containing this
+# file is a reasonable substitute
+PPRZ_HOME = os.getenv("PAPARAZZI_HOME", os.path.normpath(os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                                                      '../../..')))
 # Class for all settings
 class PaparazziACSettings:
     "Paparazzi Settings Class"
@@ -18,7 +22,7 @@ class PaparazziACSettings:
 
     def __init__(self, ac_id):
         self.ac_id = ac_id
-        paparazzi_home = os.getenv("PAPARAZZI_HOME")
+        paparazzi_home = PPRZ_HOME
         paparazzi_conf = os.path.join(paparazzi_home, 'conf')
         conf_xml_path = os.path.join(paparazzi_conf, 'conf.xml')
         conf_tree = etree.parse(conf_xml_path)